TRIM25 enhances hypoxia signaling by catalyzing K11-linked polyubiquitination and stabilization of HIF-α

TRIM25 is an E3 ubiquitin ligase involved in various cellular processes due to its enzymatic activity. In particular, it plays a role in antiviral innate immunity. Here, we demonstrate that TRIM25 modulates hypoxia signaling. TRIM25 interacts with HIF-1α and HIF-2α, stabilizing them. TRIM25 catalyzes K11-linked polyubiquitination of HIF-1α at K719 and K721 and of HIF-2α at K709. This results in the stabilization of the proteins and enhanced hypoxia signaling. Moreover, TRIM25-mediated augmentation of hypoxia signaling depends on HIF-1α. Trim25-deficient mice are more sensitive to hypoxia, and zebrafish lacking trim25 show a similar phenotype. These data reveal TRIM25's role in regulating hypoxia signaling and provide insight into a new mechanism that modulates the stabilization and activity of HIF-1α and HIF-2α.